Thursday, December 20, 2012

Latest Env. Can. warning

A Colorado low is tracking northeast towards lower Michigan and is intensifying into a winter storm as expected. Snow ahead of this storm will arrive over areas near Georgian Bay later this afternoon then quickly spread eastward into the Ottawa and St Lawrence valleys this evening.

The snow will quickly become heavy at times this evening and continue tonight and through Friday with total snowfall amounts of 15 to 25 cm expected across the district by Friday evening. Over Eastern Ontario snowfall rates up to 5 cm per hour will be quite possible during the height of this snowstorm, which is expected to be overnight into Friday morning. Total snowfall amounts could be a bit less in the St Lawrence Valley due to the possibility of mixing with some rain on Friday.

Brisk easterly winds will also cause low visibility at times in blowing snow.

As the Colorado low tracks east across Southern Ontario into New York State, it is expected to get absorbed by an East Coast low which is forecast to intensify and track northward towards Southeastern Quebec by Friday night. If this happens, heavy snow may persist in the Renfrew through Ottawa to Cornwall areas into Friday night, with potential for higher total snowfall amounts of 30 cm.